Vice-President Kamala Harris is interviewing potential contenders to be her running mate on Sunday, ahead of a battleground tour next week.
Among those travelling to Washington, DC, to meet Ms Harris are Governor Josh Shapiro, Senator Mark Kelly and Governor Tim Walz.
The choices for the Democratic vice-president has been narrowed to a group of five, according to CBS, the BBC’s US partner.
A decision is required before the Democratic National Convention, which starts on 19 August in Chicago.
It is unclear whether other potential candidates, including Kentucky Governor Andy Beshear or Transportation Secretary Pete Buttigieg, were scheduled to meet with Ms Harris.
Harris officially became the Democratic presidential nominee on Friday in a vote of party delegates.
Once Ms Harris’s running mate is announced, the two are expected to tour the battleground states.
Mr Shapiro has seen high approval ratings since he was elected in 2022 and could help Ms Harris capture Pennsylvania – a must-win state in the race for the White House.
Arizona Senator Mark Kelly, a former Navy pilot and Nasa astronaut, has become a leading voices on gun safety and his strong border stance and occasional criticisms of the Biden administration could help appeal to independent and conservative voters.
Mr Walz, who served 12 years in Congress before becoming governor of Minnesota in 2019, gained national attention for his strategy calling Donald Trump and JD Vance “weird”.
On Friday President Joe Biden said he had spoken to Ms Harris about her search for a running mate. Asked what qualities she should look for in a vice-presidential candidate, he said: “I’ll let her work that out.”
Potential partners to join Ms Harris on the Democratic ticket for November’s election face an exhaustive vetting process, having to answer up to 200 questions before being seriously considered.
Delegates do not need to vote on the vice-presidential pick.
The United Automobile Workers, a major US union representing more than 400,000 people, said its preferred vice-presidential pick was Mr Beshear, who “stood with us on the picket line and has been there for workers”.
Speaking to CBS’ Face the Nation, UAW’s Shawn Fain added that Mr Walz was also “100% behind labour”, while he criticised Mr Shapiro’s support of private school vouchers in Pennsylvania – a Republican-backed proposal to send $100m to families for private school tuition and school supplies.
